Richard Williams

I have worked at CEH for over 30 years, having completed a BSc in chemical engineering at University College London. My main expertise is in the behaviour and fate of chemicals in the environment and to use this understanding to make predictions of environmental concentrations of these chemicals in aquatic systems and soils.

Current work

I have particular experience in working with diffuse pollution from agriculture (mainly pesticides) and my current interests are around point source releases from sewage treatment works and industrial effluents (steroid oestrogens, alkyl phenols, phosphorus, pharmaceuticals and nano-particles).

I combine the environmental concentrations predicted by computer models for chemicals or groups of chemicals to levels of these chemicals which are known to cause environmental harm in order to make risk assessments. One of the most effective ways to convey these risk assessments is through maps of river systems colour coded according to the likely level of harm. To do this CEH has developed spatially explicit river models which generate geographically referenced outputs that can be displayed using mapping software tools.

I also have a long-held interest in modelling dissolved oxygen, Biochemical Oxygen Demand*, ammonia and nitrate in rivers. Currently I am trying to improve the modelling of dissolved oxygen at short time steps (hourly) and relating these concentrations to flow conditions, nutrient availability and growth of macrophytes and algae in the river.

* Biochemical or biological oxygen demand (BOD) is the amount of oxygen required by aerobic bacteria and other micro-organisms to decompose the organic matter in a litre of water. It is used as a measure of the degree of water pollution from sources such as sewage.